Most of the land area consists of a plateau some 1,200 m (4,000 ft.) above sea level and strewn with mountains. The Zagros and Alborz ranges stamp a “V” upon the plateau; the apex is in the northwest, and within the lower area between the arms are to be found salt flats and barren deserts. Most of the drainage is from these two great ranges into the interior deserts, with limited drainage into the Caspian Sea and the Persian Gulf. The ranges run in parallel files, enclosing long valleys that provide most of the agricultural land. Mt. Damavand Peak, northeast of Tehran, rises to 5,671 m (18,605 ft.), while the Caspian littoral is below sea level and has a semitropical climate. Only the Karun River, emptying into the Persian Gulf, is navigable for any distance, but the rivers that rush down from high altitudes offer fine sources of power. Harbors of limited depth are found along the Persian Gulf, and the Caspian Sea has similar facilities for coastal fishing and trade.
Iran has a continental type of climate, with cold winters and hot summers prevalent across the plateau. The Caspian littoral is warm and humid throughout the year, and the annual rainfall is about 100–150 cm (40–60 in). Snow falls heavily on the mountain peaks and is the principal source of water for irrigation in spring and early summer. Clear days are the rule, for the sky is cloudless more than half the days of each year. The seasons change abruptly. By the Persian New Year (the first day of spring), orchards are in bloom and wild flowers abound.
FLORA AND FAUNA
More than one-tenth of the country is forested. The most extensive growth is found on the mountain slopes rising from the Caspian Sea, with stands of oak, ash, elm, cypress, and other valuable trees. On the plateau proper, areas of scrub oak appear on the best-watered mountain slopes, and villagers cultivate orchards and grow the plane tree, poplar, willow, walnut, beech, maple, and mulberry. Wild plants and shrubs spring from the barren land in the spring and afford pasturage, but the summer sun burns them away. Bears, wild sheep and goats, gazelles, wild asses, wild pigs, panthers, and foxes abound. Domestic animals include sheep, goats, cattle, horses, water buffalo, donkeys, and camels. The pheasant, partridge, stork, and falcon are native to Iran. The government has established wildlife sanctuaries such as the Bakhtegan Wildlife Refuge, Turan Protected Area, and Golestan National Park. The hunting of swans, pheasants, deer, and a number of other animals and birds is prohibited.
Present-day Iranians, or Persians, are considered to be direct descendants of the Aryans who moved into the plateau in the second millennium BC. They speak Persian, or Farsi, and number more than half the total population. In the Zagros range and its extensions are to be found the Kurds, Lurs, Bakhtiari, and Qashqai; the first three are said to be of stock similar to the Iranian element, and they speak languages stem from ancient Indo-European ones. At various times after the 10th century, Turkish tribes settled in the region, and for this reason Turkish-speaking groups are still found in several parts of the country. One-eighth of total population dwells in East and West Azerbaijan, and there are sizable groups of Azerbaijanis in major cities elsewhere, including Tehran. Arab groups arrived about and after the 7th century; their descendants live in the south and southwest and in scattered colonies elsewhere.
In general, non-Iranian elements are to be found along the perimeter of the country. Of these, certain nomadic groups move back and forth across their specific directions. Tribal groups have been a conspicuous element in Iran for many centuries, migrating vertically in spring and fall between high mountain valleys and hot, lowland plains. The important migratory groups include the Qashqai, Bakhtiari, Balochi, and Turkmen, however a large proportion of these groups are now settled. The nomadic way of life is on the decline, and official policy has sought to resettle these groups on farmlands.
According to the latest estimates, Persians account for 51% of the population, Azeri 24%, Gilaky and Mazandarani 8%, Kurds 7%, Arab 3%, Lurs 2%, Balochi 2%, and Turkmen 2%.
Farsi, commonly called Persian in the West, is the official language of Iran. An Indo-European language of the Indo-Iranian group, Farsi derives from ancient Persian, with a mixture of many Arabic words. Arabic characters and script are used in writing modern Persian. Dialects of Turkish, or Turki—especially Azeri, the language of the Azerbaijanis—are spoken throughout northwestern Iran, by the Qashqai tribe in the southwest, and in parts of the northeast by Turkmen tribes and others. The Lurs, Kurds, and Bakhtiari have a kind of languages and dialects of their own that descend from earlier Indo-European ones, and the Balochi language spoken in southeastern of Iran also is of Indo-European origin. A small number of Brahui in the southeast speak a Dravidian language. About 58% of the population speaks Persian or Persian dialects, 26% Turkic or Turkic dialects, 9% Kurdish, 2% Luri, 1% Balochi, 1% Arabic, 1% Turkish, and 2% other.